[Andris6000]

Are you sure that is a "problem", not a "feature"?

Yeah am pretty sure this is a problem because RHAF never flew with these kinds of markings on the tail ...
I never seen it on no photos, never red about such things like this in a book or anything .

Does it do this on the Default skin?

Planemad

Yes it does it on every single skin if the markings are switched on.

Did it appear with some mod or was it there in the original 4.09?

I guess with HSFX It started to appear